1. Field of the Invention
The present invention relates to a radiation furnace assembly for use in heating parts.
2. Description of the Prior Art
Radiation furnace assemblies used to heat parts typically include a muffle surrounded by a casing with top and bottom heating elements located inside the casing. The top and bottom heating elements are positioned adjacent to a top side and bottom side of the muffle to heat a main portion of the chamber within the muffle. The top and bottom heating elements are controlled by either a single control device or independent control devices to adjust the temperature of the elements to maintain a uniform temperature inside the muffle.
It is also common in the art to connect a side heating element to the casing such that it is disposed adjacent to a first side wall of the muffle. The side heating element acts as a separate heating mechanism for heating the main portion of the chamber within the muffle. The side heating element is controlled by the same control device as the top and bottom heating elements. Subsequently, the three heating elements are adjusted simultaneously by the control device.
The disadvantage of the prior art is the inability to increase the temperature in different portions of the chamber independently from the main portion of the chamber. It is common in the brazing industry to braze a part that has a large mass differential on one side. When using a typical radiation brazing furnace with simultaneously controlled heating elements, it is difficult to ensure adequate and efficient brazing throughout the part.
The present invention is a radiation furnace assembly for use in heating parts. The radiation furnace assembly includes a muffle having a top side, a bottom side, a first side wall and a second side wall defining a chamber for receiving the part to be heated. The chamber is divided into a main heating portion and a first side heating portion. A casing substantially surrounds the muffle to insulate the chamber and to reflect heat back towards the muffle. Top and bottom heating elements are located inside of the casing and are positioned adjacent to the top side and bottom side of the muffle, respectively. A first control device is connected to at least one of the top and bottom heating elements to adjust their temperature to control the temperature within the main heating portion of the chamber. A first side heating element is also connected to the inside of the casing and is positioned adjacent to the first side wall of the muffle. The first side heating element is positioned to heat the first side heating portion of the chamber. A second control device is connected to the first side heating element to adjust the temperature of the first side heating element independently of the top and bottom heating elements. The second control device is used to increase the temperature within the first side heating portion of the chamber that is adjacent to the first side wall of the muffle.
The primary advantage of the present invention is the ability to create a temperature differential within the chamber by increasing the temperature of the first side heating element independently of the top and bottom heating elements. It is common in the brazing industry to braze a part that has a large mass differential on one side. As such, the sufficiency of brazing is substantially increased by increasing the temperature in the portion of the chamber that houses the largest concentration of mass.
In addition to the aspect of better brazing quality, the use of an independently controlled first side heating element also significantly reduces process time, resulting in higher efficiencies and consequently, less costly parts or assemblies.